Snap inline box boundaries to layout units during line breaking.

third_party/WebKit/Source/core/layout/line/BreakingContextInlineHeaders.h

 /*
  * Copyright (C) 2000 Lars Knoll (knoll@kde.org)
  * Copyright (C) 2003, 2004, 2006, 2007, 2008, 2009, 2010, 2011 Apple Inc. All right reserved.
  * Copyright (C) 2010 Google Inc. All rights reserved.
  * Copyright (C) 2013 Adobe Systems Incorporated.
  *
  * This library is free software; you can redistribute it and/or
  * modify it under the terms of the GNU Library General Public
  * License as published by the Free Software Foundation; either
  * version 2 of the License, or (at your option) any later version.
@@ skipping 260 matching lines @@
 }
 
 inline void BreakingContext::increment()
 {
     // Clear out our character space bool, since inline <pre>s don't collapse whitespace
     // with adjacent inline normal/nowrap spans.
     if (!m_collapseWhiteSpace)
         m_currentCharacterIsSpace = false;
 
     m_current.moveToStartOf(m_nextObject);
+
+    // When the line box tree is created, this position in the line will be snapped to
+    // LayoutUnit's, and those measurements will be used by the paint code.  Do the
+    // equivalent snapping here, to get consistent line measurements.
+    m_width.snapUncommittedWidth();
+
     m_atStart = false;
 }
 
 inline void BreakingContext::handleBR(EClear& clear)
 {
     if (m_width.fitsOnLine()) {
         LineLayoutItem br = m_current.object();
         m_lineBreak.moveToStartOf(br);
         m_lineBreak.increment();
 
@@ skipping 621 matching lines @@
 
     if (style.textIndentType() == TextIndentHanging)
         shouldIndentText = shouldIndentText == IndentText ? DoNotIndentText : IndentText;
 
     return shouldIndentText;
 }
 
 }
 
 #endif // BreakingContextInlineHeaders_h